Impulse generator



y 1934- A. BRAscH ET AL ,957,008

IMPULSE GENERATOR Filed Sept. 11, 1931 Fig.1. Ti .2.

l f 2 i IN VEN TORS I A TTORNEYS.

I 772 /Z Braschflanyzf 772 Pah/ Patented May 1, 1934 PATENT OFFICE IMPULSE GENERATOR Arno Brascli, Fritz Lange, and Max Dahl,

Berlin, Germany Application September 11, 1931, Serial No. 562,406 In Germany September 11, 1930 14 Claims. (Cl. 171-97) As a very recent innovation in the art, an everincreasing tendency is making itself noticeable to acquire the assistance of extremely high voltages, if only by way of impulse .or intermission,

for testing purposes in the trade, or for the purpose of scientific investigation. In this connection reference may be made to the testing of open line insulators and the generation of traveling waves, wherein the principal feature concerned is the generation of voltages of approximately that strength in which the same might occur assuming the line were struck by lightning, i. e., a strength amounting to several million volts.

It is also a fact that quite recently various problems of an acute nature have cropped up, which are conditional on the generation and control of high electrical potentials. Thus, for example, with the assistance of these potentials, efforts have been made with the help of corpuscular rays accelerated in higlr vacuum tubes to exert influence on the inner atomic structure of matter, and to produce conversion of elements. Particularly inexperlments of this nature, in which'merely the average output constitutes the important factor, the impulse or intermission processis equivalent if not superior to continuous operation such as derived by the use of Tesla or alternating current, as for short-time operations it is possible to employ in the construction of these apparatus materials having a much lower power of insulation, since for brief spaces of time the resistance of more or less inferior insulating materials is still extremely high.

Beyond this it is also possible to employ extremely high impulse voltages for medicinal purposes in such cases in which the desired object is the treatment in intensive form with rays resembling those of radium, i. e., channel and cathode rays, whereby, owing to the considerable intensities concerned, the period of radiation naturally is required to be very short, a bundle of channel rays of 1 milliampere and potential of several million volts being equivalent to the intensity of radiation of approximately 100 kilogrammes of radium.

The impulse apparatus used heretofore and generally speaking constructed according to the method of E. Marx, are operated exclusively in air by atmospheric pressure. The Marx device consists of an arrangement whereby a plurality of condensers are charged in parallel through resistors of such a value that when the charge reaches a predetermined value the condensers are automatically discharged in series with a load circuit, thereby securing a discharge voltage which is for a very small interval of time much larger than the charging voltage. If, however, it is a question of several million volts, these apparatus, owing to the large amount of space required, will be capable of production only at very largeexpense, sothat the same are hardly available to' small institutions or undertakings, and more particularly laboratories or medical institutions.

It is, therefore, the primary object of the present invention to provide a reliable and compendious type of apparatus for any desired voltage suchas required for testing or atomic purposes. Other objects and advantages of the invention will become apparent as the description proceeds.

It is well known that insulating liquids possess for a brief space of time a very considerable disruptive strength. Whereas, generally speaking, a disruptive strength of field amounting to 40,000 to 60,000 volts/cm. is assumed in respect of commercial oil, and one of 200,000 to 300,000 volts/cm. in respect of very pure oils, this value when subjected to impulse action increases dependent on the duration of the impulse (10 10- sec.) to 500,000-1,300,000 volts per cm.

Numerous experiments conducted have shown that the disruptive value is approximately the same with all kinds of oil, including very impure oil, and that it is merely the duration of the impulse which constitutes the decisive factor, so that operations may accordingly be performed with cheap and impure oil. Since the final high voltage is only effective for an extremely brief space of time, it is obviously the correct thing to embed impulse voltage systems of this kind in liquid insulating materials. However, the fact of the delay above referred to in the case of brief periods of time also discloses that it is impossible to also allow the operation of the spark gap to be initiated simultaneously under oil, as in this case an increase of voltage up to ten times the 95 amount would be required. According, therefore to the invention, the spark gaps are located in. separate chambers containing gas under pressure, whereby, according to the tests made, a delay which is capable of measurement does not take 100 place. This combination has the advantage that the large ball gaps otherwise necessary in the case of normal impulse apparatus are entirely obviated, and the whole connection may be performed in small, handy chambers. It is well 105 known that the disruptive strength of gases increases up to about 70 atmospheres in proportion with the prevailing pressure. If, therefore, the spark distance in atmospheric pressure amounts at a certain voltage between points to 10 cm., 110

this distance at a pressure of 10 atmospheres will amount to only 1 cm. However, it is naturally quite possible to provide for any desired pressure in the small chambers. An additional advantage resides in the fact that the regulation of this gap in order to produce diflerent voltages is not, as heretofore,performed mechanically, but may be effected simply by increased or decreased compression in the chambers, and the pressure measured on a manometer.

In order to avoid creeping discharges at the condensers the insulating liquid employed may be placed under a certain pressure to preclude any possibilities in this direction. In this manner the disruptive strength a the solid dielectric is at the same time greatly increased. The tendency to sliding discharge, which is produced by high frequency occurrences upon the connection, may also be very greatly diminished by the use of an insulating liquid having a high dielectric constant.

To avoid large dimensions 01' the pressure container, or to confine the use of high-quality insulating substances to a minimum, this container is made only of a sufilcient size to Just receive the condensers, and is placed in a second larger container. Since the liquid in this second container is acted upon only by the final impulse voltage, and not by the charging voltage acting for some length of time, it is possible to employ in this outer container relatively good conductive liquids, for example water. When using relatively good conductive liquids it is then naturally necessary to provide an additional spark gap, so that the charging voltage is at no time in connection with the poor external resistance of the liquid, but that on the other hand the high voltage impulses are connected with the liquid, via the gap, so that undesirable ruptures do not occur at other points. The very possibility of being able to employ a cheap substance, such as water, as insulating liquid should permit of voltages of 50,000,000-100,000,000 volts. In order to avoid appreciable ruptures, impulse genera tors of the kind described permit the placing or the articles to be tested, such as insulators or discharge tubes, in the outer container, and to be operated with high voltage.

The invention will now be described more fully with reference to the accompanying drawing, in which Fig. 1 shows diagrammatically a longitudinal section through an impulse generator.

Fig. 2 is a similar view of a modified form of embodiment.

Fig. 3 is a longitudinal section on enlarged scale taken through the communicating pressure spark gap employed in the impulse generator according to Fig. 2.

Referring now to the drawing, a is an outer container preferably composed of metal and wholly or partially filled with insulating oil b 01' poor quality. In place of the oil it is also possible to employ water. In Fig. 1c is the insulated passage conducting the impulse to the desired apparatus, for example X-ray tube or other medicinal apparatus. There may also be connected with the passage insulators or other apparatus for the purpose of testing the disruptive strength. Within the outer container a there is provided an inner container d, which is filled with oil e of a higher quality, or having a greater specific inductive capacity respectively. In this vessel d there are furnished charging resistances f. The one resistance is joined up with the cha ging voltage, while the second resistance is connected with earth. In the container d there are also situated the spark gaps a, which by means of insulated pipes i, which include a manometer k, are connected with a compressed air source. A special series spark gap h is provided at the end of the gap a. The one ball of the gap h is in accordance with Fig. 1 connected by the line 1 with the reception pole of the impulse generator, whereby this line i at the point where the same is passed through the insulator c is insulated against the outer container. Between the single gaps there are situated the capacities or condensers q, the armatures of which are connected on the one hand with the charging resistance, and on the other hand with the particular poles.

By regulating the compressed air conducted to the single spark gaps through the pipes i, in which connection the pressure may be read on the manometer it, it is possible to graduate the manometer to constitute a voltmeter, and to employ the same in this capacity. The voltage may, therefore, be varied as desired within different limits, in accordance with the degree of pressure, which may be adjusted by means of valves or the like.

The form of embodiment according to Fig. 2 agrees in substance with that in Fig. 1. In this case, however, there is introduced into the container a the apparatus 1 which is to be tested as regards its disruptive strength.

In Fig. 2, therefore, there is shown an insu lator applied directly to the series spark gap h and tested in the apparatus itself. In place 0! the insulator 1 there may be fitted a discharge tube, so that the rays emanating from the discharge tube pass directly from the interior or the apparatus towards the outside on to the article or object under treatment.

In the embodiment according to Fig. 2 the spark gaps are located in chambers, which are open towards the oil space of the outer container d, so that the oil is capable of penetrating in part into the same. The oil space itself is connected by means 0! a pipe i, over a manometer 1:, either with a compressed air source or with an oil feed pipe, which may be maintained under pressure as desired. In contradistinction to the form of embodiment in Fig. 1 the single air pipes communicating with the spark gap cham- I bers are omitted in Fig. 2. In the latter embodi-' ment the pressure is conveyed evenly by the'oil' or other liquid. so that all spark gaps are under the same pressure.

Fig; 3 shows on enlarged scale one or the spark gaps employed in Fig. 2. In this figure m is the oil rising in the chamber under the pressure or the oil, while 1|. is the lead to a spark gap pole p and o the lead to the second pole p.

It will be understood that no restriction is made to the specific forms of embodiment shown in the drawing, and that various modifications are quite possible within the meaning of the above description and the annexed claims without departing from the spirit of the invention.

What we claim as new and desire to secure by Letters Patent is:

1. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source conin parallel with the said condensers through the medium of the said resistances, gasfllled chambers, and a plurality of spark gaps in the-said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

2. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid or high specific inductive capacity within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality oi condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, gas-filled chambers, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said sparkgaps break down.

3. A device for generating extremely high potentials,comprising in substance a container, an insulating fluid within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said chambers, the said condensers being connected in. series through the medium of the said spark gaps when the said spark gaps break down.

4. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid of high specific inductive capacity within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

5. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a regulable pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

6. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid of high specific inductive capacity within the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a regulable pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said cham bers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

'7. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, gasfilled chambers, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

8. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid of high specific inductive capacity under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, gas-filled chambers, and a plurality of spark'gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

9. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel, with the said condensers through the medium of the saidv resistances, chambers filled with gas at a pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gapsv break down.

10. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid of high specific inductive capacity under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a pressure exceeding atmospheric pressure, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

11. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a pressure exceeding atmospheric pressure and communicating at their bottoms with the said container, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down.

12. A device for generating extremely high potentials, comprising in substance 9. container, an insulating fluid oi high speciflc inductive capacity under pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality oi! condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers filled with gas at a pressure exceeding atmospheric pressure and communicating at their bottoms with the said container, the said condensers being connected in series through the medium of the said gaps when the said spark gaps break down.

13. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid under regulable pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality oi. condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistances, chambers fllled with gas at a regulable pressure exceeding atmospheric pressure and communicating with the said container, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium or the said spark gaps when the said spark gaps break down.

14. A device for generating extremely high potentials, comprising in substance a container, an insulating fluid of high specific inductive ca-- pacity under regulable pressure in the said container, and an impulse generator with short discharge period in the said fluid, the said impulse generator comprising a plurality of condensers, a plurality of resistances, a potential source connected in parallel with the said condensers through the medium of the said resistance, chambers filled with gas at a regulable pressure exceeding atmospheric pressure and communicating with the said container, and a plurality of spark gaps in the said chambers, the said condensers being connected in series through the medium of the said spark gaps when the said spark gaps break down. 

